Amblyomma Mixtum Research Articles

Richness and abundance of ticks associated with domestic animals at different altitudes in Southern Mexico

The objective of this study was to determine the richness, abundance, and altitudinal distribution of ticks collected from domestic animals in five municipalities and sixteen distinct communities along the Pacific coast of southern Mexico in Chiapas. Ticks were sampled from dogs, horses, and cows in each range. A total of 311 hosts were sampled, of which 264 (85 %) were dogs, 26 (8 %) were horses, and 21 (7 %) were cows. Of these, 83 (26 %), 17 (5 %), and 7 (2 %) hosts were infested, respectively. A total of 583 ticks were collected, representing four genera and six species. The most prevalent species was Rhipicephalus linnaei (68.61 %, n = 400), followed by Rhipicephalus microplus (0.51 %, n = 3), Amblyomma ovale (1.71 %, n = 10), Amblyomma mixtum (1.71 %, n = 10), Ixodes ci. boliviensis (2.22 %, n = 13), and Dermacentor dissimilis (25.21 %, n = 147). Of the identified ticks, A. mixtum, A. ovale, R. microplus, and R. linnaei were distributed at elevations between 0 and 1000 m, while at elevations between 1000 and 2000 m, only the species I. ci. boliviensis and D. dissimilis were found. The characteristics of each locality are discussed in order to explain the abundance of ticks and to assess their potential risk as vectors of public health pathogens.

Impact of climate change on the geographical distribution of ticks of public health significance in Colombia: Amblyomma ovale (Ixodida: Ixodidae), the Amblyomma maculatum (Ixodida: Ixodidae) complex and the Amblyomma cajennense (Ixodida: Ixodidae) complex.

Ticks of the Amblyomma maculatum (Ixodida Ixodidae) complex, the Amblyomma cajennense (Ixodida Ixodidae) complex and Amblyomma ovale (Ixodida Ixodidae) are known to transmit various Rickettsia species in Colombia, but their exact distribution is unknown. We built several models based on current climate and projected future climate changes using a maximum entropy approach. A total of 314 records of the A. cajennense complex (65.9%; n = 207), A. ovale (22.9%; n = 72), and the A. maculatum complex (11.1%; n = 35) were obtained. Amblyomma ovale has a current distribution in the Pacific, Caribbean and Andean regions and could be potentially found in the Amazon. Amblyomma maculatum has a current distribution in the Andean and could potentially be found in the Caribbean and Orinoco regions. Amblyomma mixtum can be found near the Caribbean Sea and in the Pacific region, and A. patinoi is likely to be found in the Andean region and the Caribbean. In 2070, it will be possible to find an expansion of A. ovale and A. maculatum and a decrease of A. mixtum and A. patinoi. The variables that best predict the distribution of these species are isothermality (small fluctuations in temperature) and annual precipitation. Amblyomma cajennense s.l and A. ovale, A. cajennese s.l and A. patinoi, as well as A. maculatum and A. patinoi, have an important environmental sympatry. Epidemiological and acarological surveillance is crucial to investigate rickettsiosis caused by R. parkeri in A. ovale regions, by R. rickettsii in A. patinoi and A. mixtum areas, and by R. parkeri s.s in A. maculatum regions.

Infestation of Cattle with the Tick Amblyomma mixtum in the States with the Highest Cattle Inventory in Mexico

A Objective: The Amblyomma mixtum tick is one of the main parasites affecting cattle in Mexico. Epidemiological records of A. mixtum in leading states in the national cattle industry, such as Jalisco, Chiapas, Michoacán, Tabasco, and Veracruz, are outdated since this tick species was previously classified as A. cajennense. The objective was to update the records of the A. mixtum tick in the states of Jalisco, Chiapas, Michoacán, Tabasco, and Veracruz, as well as the main ixodicide molecules used for its control. Methodology: From March 2022 to July 2023, ticks were collected from cattle in 46 bovine production units (BPUs) distributed in the states mentioned above. Identification was performed using standardized taxonomic keys. Scanning electron microscopy was performed on specimens corresponding to A. mixtum. Results: Out of a total of 619 specimens of the genus Amblyomma from 22 PBUs, it was confirmed that 100% correspond to the species A. mixtum. Amitraz, an ixodicide molecule belonging to the chemical class of amidines, was used in 63.2% of the BPUs where the presence of A. mixtum was also reported. Conclusions: This research confirms cattle infestation with A. mixtum in states with the highest cattle production in Mexico. Further studies with a focus on resistance and extension are required to prolong the usefulness of available tools, including ixodicides, for integrated control of A. mixtum infestations where this tick infests cattle in Mexico.

Bacterial community of ticks (Acari: Ixodidae) and mammals from Arauca, Colombian Orinoquia

Ticks are obligate hematophagous ectoparasites of vertebrates and are relevant worldwide due to the number of bacterial and other pathogens they can transmit. To date, the knowledge about the microorganisms that ticks harbor and transmit to their hosts is incipient. In this study, 24 samples of mammals belonging to four taxonomic orders and ticks of the genera Amblyomma and Rhipicephalus from the Orinoco region of Colombia were analyzed to described and compare the bacterial microbiome. Genetic extraction was performed, and the V3–V4 region of the 16S rRNA gene was amplified by PCR. Libraries were created, and those samples with adequate quality indices were sequenced using Illumina MiSeq technology. Bacterial taxonomic assignment analyses were conducted through Amplicon Sequence Variants (ASVs) and Operational Taxonomic Units (OTUs). The results correspond to 16 samples that passed the quality filters, with 3218 OTUs (415 families). Although a considerable number of unknown bacteria was found, Enterobacteriaceae, Beijerinckiaceae, Moraxellaceae, and Burkholderiaceae are the most prevalent families, and the presence of the genera Coxiella, Escherichia-Shigella, Enterobacter, which can harbor pathogenic species was confirmed. In individuals of Amblyomma mixtum found actively feeding on Hydrochoerus hydrochaeris, bacteria of the genera Escherichia-Shigella and Enterobacter were documented. Similarly, Rhipicephalus microplus found actively feeding on Odocoileus virginianus cariacou shared Escherichia-Shigella. Ralstonia was shared among the blood samples of H. hydrochaeris, while Anaplasma and Eubacterium were shared in blood and liver samples of O. v. cariacou. Shared bacteria between A. mixtum and R. microplus included Bacillus, Coxiella, and Escherichia-Shigella. The results highlight the need of additional studies in other natural regions of Colombia and other American countries where tick-borne diseases have been detected. Likewise, the recorded data are the first at the level of bacterial communities in ticks of the family Ixodidae and provide valuable knowledge for the understanding host-tick and pathogen interactions.

Ticks (Acari: Ixodidae) on resident and migratory wild birds in Orinoquia region, Colombia

Several species of hard ticks, including those of the genera Ixodes, Haemaphysalis, Amblyomma, and Rhipicephalus, are of medical and veterinary importance and have been reported in association with Neotropical wild birds. Colombia, known for its great bird diversity, has 57 confirmed tick species. However, there are few studies on the association between wild birds and ticks in Colombia. The Orinoquia region, a migratory center in Colombia, provides a unique opportunity to study wild bird-tick associations and their implications for tick-borne disease dynamics. Our study, conducted between October and December 2021, aimed to identify hard ticks infesting resident and migratory wild birds in the department of Arauca and to assess the presence of bacteria from the genera Anaplasma, Borrelia, Ehrlichia, Rickettsia, and piroplasms. A total of 383 birds were examined, of which 21 were infested. We collected 147 ticks, including Amblyomma dissimile (larvae), Amblyomma longirostre (nymphs), Amblyomma mixtum (adults), and Amblyomma nodosum (larvae and nymphs). We did not detect bacterial DNA in the tested ticks; however, piroplasm DNA was detected in ticks from three of the infested birds. Of the 21 bird-tick associations, six are new to the Americas, and interesting documentation of piroplasm DNA in A. longirostre, A. nodosum, and A. dissimile ticks from wild birds in the region. This study provides valuable insights into the ticks associated with wild birds and their role in the dispersal of ticks and pathogens in Colombia, enhancing our understanding of tick life cycles and tick-borne disease dynamics.

New hard tick (Acari: Ixodidae) reports and detection of Rickettsia in ticks from Sierra Nevada de Santa Marta, Colombia

The Sierra Nevada de Santa Marta (SNSM), located in northern Colombia, is considered a geographical island with high levels of biodiversity and endemism. However, little is known about tick species and their associated microorganisms at the SNSM. In this study we sampled host-seeking ticks in areas of the town of Minca within the SNSM. We collected 47 ticks identified as Amblyomma pacae, Amblyomma longirostre, Amblyomma ovale, Amblyomma mixtum, Haemaphysalis juxtakochi, Ixodes sp. cf. Ixodesaffinis and Ixodes sp. Of these ticks, we tested for Rickettsia spp. by amplifying the gltA, SCA1, and 16S rRNA genes via PCR. Rickettsia amblyommatis was detected in one pool of 3 larvae and in a female of A. pacae. Additonally, we isolated Rickettsia sp. belonging to the group of spotted fevers in larvae of A. longirostre. This study reports new findings of six species of ticks and two species of Rickettsia within the SNSM.

Exotic ticks removed from German travelers.

We report the finding of five nymphs and three adult ticks attached to German tourists while traveling the American continents. All eight specimens were morphologically identified and confirmed genetically using the 16S rRNA gene and screened for Rickettsia spp. infections. Five tick species were identified: one Amblyomma mixtum nymph from Ecuador, one Amblyomma varium nymph from Colombia, three Amblyomma coelebs nymphs from Costa Rica, one Amblyomma americanum male from the USA, one Dermacentor andersoni female and one D. andersoni male from Canada. Tick-borne microorganisms screening using the pan-Rickettsia-PCR resulted in two positive and six negative ticks. The A. mixtum nymph was positive for Rickettsia amblyommatis, while the D. andersoni female was positive for Rickettsia peacockii.

Molecular screening of tick-borne microorganisms in ticks from rural areas of Panama, with the first record of Ehrlichia minasensis in Rhipicephalus microplus from Central America.

During a molecular screening of rickettsial, borrelial and protozoal agents in ticks from rural areas of Panama, we detected DNA of Rickettsia amblyommatis in four Amblyomma mixtum collected from horses in a locality in Los Santos province. Ehrlichia minasensis and Anaplasma marginale were identified from three and two Rhipicephalus microplus, respectively, collected on cows from Chiriqui province. No DNA from other tick-borne agents was found. These results increase the information of R. amblyommatis and A. marginale in Panama, and also mark the first record of E. minasensis in Central America.

Efficacy of the Vaccine Candidate Based on the P0 Peptide against Dermacentor nitens and Ixodes ricinus Ticks.

The control of ticks through vaccination offers a sustainable alternative to the use of chemicals that cause contamination and the selection of resistant tick strains. However, only a limited number of anti-tick vaccines have reached commercial realization. In this sense, an antigen effective against different tick species is a desirable target for developing such vaccines. A peptide derived from the tick P0 protein (pP0) conjugated to a carrier protein has been demonstrated to be effective against the Rhipicephalus microplus, Rhipicephalus sanguineus, and Amblyomma mixtum tick species. The aim of this work was to assess the efficacy of this peptide when conjugated to the Bm86 protein against Dermacentor nitens and Ixodes ricinus ticks. An RNAi experiment using P0 dsRNA from I. ricinus showed a dramatic reduction in the feeding of injected female ticks on guinea pigs. In the follow-up vaccination experiments, rabbits were immunized with the pP0-Bm86 conjugate and challenged simultaneously with larvae, nymphs, and the adults of I. ricinus ticks. In the same way, horses were immunized with the pP0-Bm86 conjugate and challenged with D. nitens larva. The pP0-Bm86 conjugate showed efficacies of 63% and 55% against I. ricinus and D. nitens ticks, respectively. These results, combined with previous reports of efficacy for this conjugate, show the promising potential for its development as a broad-spectrum anti-tick vaccine.

First isolation of Rickettsia amblyommatis from Amblyomma mixtum in Colombia

BackgroundRickettsiae are obligate intracellular Gram-negative bacteria that are the causative agent of rickettsioses and are spread to vertebrate hosts by arthropods. There are no previous reports of isolation of Rickettsia amblyommatis for Colombia.MethodsA convenience sampling was executed in three departments in Colombia for direct collection of adult ticks on domestic animals or over vegetation. Ticks were screened for the presence of Rickettsia spp. by real-time polymerase chain reaction (qPCR) amplifying the citrate synthase gene (gltA), and the positive sample was processed for isolation and further molecular characterization by conventional PCR. The absolute and relative frequencies were calculated for several tick species variables. All products from conventional PCR were further purified and sequenced by the Sanger technique. Representative sequences of 18 Rickettsia species were downloaded from GenBank. Consensus phylogenetic trees were constructed for the gltA, ompB, ompA, and htrA genes with 1000 replicates, calculating bootstrap values through the maximum likelihood method and the generalized time reversible substitution model in the MEGA 7.0 software program.ResultsOne female Amblyomma mixtum collected on vegetation was amplified by qPCR (gltA), indicating a frequency of 1.6% (1/61) for Rickettsia spp. infection. Sequence analysis of a rickettsial isolate from this tick in BLASTn showed 100% identity with gltA (340 base pairs [bp]), 99.87% for ompB (782 bp), 98.99% for htrA (497 bp), and 100% for ompA (488 bp) to R. amblyommatis. Concatenated phylogenetic analysis confirmed these findings indicating that the isolate is grouped with other sequences of Amblyomma cajennense complex from Panama and Brazil within the R. amblyommatis clade.ConclusionsThis paper describes the isolation and early molecular identification of a R. amblyommatis strain from A. mixtum in Colombia.Graphical

Detection of Rickettsia amblyommatis and Rickettsia bellii in ticks collected from pet dogs in peri-urban and rural areas in Yucatan, Mexico.

Rickettsia species are bacteria that may cause multiple diseases in animals and humans, via transmission through multiple arthropod vectors. Routine surveillance of Rickettsia spp. within vectors is critical to determine their presence and risk to mammalian hosts within human populations. Therefore, to better characterize the circulating Rickettsia species in an understudied region we targeted pet dogs to survey. Ticks were collected from pet dogs in three populations of the Yucatan where we tested for the presence of Rickettsia spp. by PCR in metagenomic DNA. In these ticks removed from pet dogs we detected Rickettsia amblyommatis and Rickettsia bellii in Amblyomma auriculatum, Amblyomma ovale and Amblyomma mixtum ticks obtained in a rural community in the Mexican state of Yucatan. This is the first report detecting both species for this state in Mexico, underpinning the importance of more routine surveillance.

Ticks and tick-borne rickettsiae from dogs in El Salvador, with report of the human pathogen Rickettsia parkeri

Twelve tick species have been reported in El Salvador; however, information regarding ticks infesting domestic dogs is lacking, and pathogenic tick-borne Rickettsia species have never been reported in El Salvador. This work evaluated ticks infesting 230 dogs from ten municipalities in El Salvador from July 2019 to August 2020. A total of 1,264 ticks were collected and identified into five species: Rhipicephalus sanguineus sensu lato (s.l.), Rhipicephalus microplus, Amblyomma mixtum, Amblyomma ovale, and Amblyoma cf. parvum. The tick R. sanguineus s.l. was the most frequent species in all localities (81.3% of sampled dogs), followed by Amblyomma mixtum (13.0%), Amblyomma ovale (10.9%) and Amblyomma cf. parvum (10.4%). The overall mean intensity of tick infestation was 5.5 ticks/dog. The highest specific mean intensity value was for R. sanguineus s.l. (4.8 ticks/dog), varying from 1.6 to 2.7 ticks/dog for the three Amblyomma species. From a random sample of 288 tick specimens tested molecularly for the presence of rickettsial agents, three spotted fever group Rickettsia were detected: Rickettsia amblyommatis in 90% (36/40) A. mixtum, 46% (11/24) A. cf. parvum, 4% (7/186) R. sanguineus s.l., and 17% Amblyomma spp.; Rickettsia parkeri strain Atlantic rainforest in 4% (1/25) A. ovale; and an unnamed rickettsia agent, designated as ‘Rickettsia sp. ES-A.cf.parvum’, in 4% (1/24) A. cf. parvum. Our finding of R. parkeri strain Atlantic rainforest in A. ovale is highly relevant because this agent has been associated to spotted fever illness in other Latin American countries, where A. ovale is implicated as its main vector. These findings suggest that spotted fever cases caused by R. parkeri strain Atlantic rainforest could be occurring in El Salvador.

Ticks (Parasitiformes: Ixodida: Ixodidae) parasites of wild Baird’s tapirs (Mammalia: Perissodactyla) in the Yucatan Peninsula, Mexico

ABSTRACT Tapirs are common hosts of ticks and an individual can be infested by up to seven different tick species. We explored the parasitic tick fauna associated with wild Baird’s tapirs (Tapirus bairdii) from the Yucatan Peninsula. A total of 326 ticks of 10 species of the Family Ixodidae were collected from 15 tapirs. We found a range of one to six tick species per host, but most of the tapirs were parasitized by two or three tick species. We tested the relationship between body condition, sex, and age classes of the tapirs versus the number of tick species on each host. The most common tick species was Amblyomma mixtum found on 93% of the hosts. Amblyomma pecarium, Amblyomma tenellum, Ixodes affinis and Rhipicephalus sanguineus sensu lato were recorded for the first-time parasitizing Baird’s tapirs. We did not find a relationship between body condition, sex, and age classes of tapirs versus the number of parasitizing tick species. Our finding demonstrates that the richness of ticks parasitizing tapirs does not depend on the biological characteristics and health status of the host, but could be determined by other factors such as habitat use and the rate of contact with domestic animals.

FIRST EVIDENCE OF THE TICKICIDE EFFECT OF ENTOMOPATHOGENIC FUNGI ISOLATED FROM MEXICAN CATTLE FARMS AGAINST AMBLYOMMA MIXTUM.

This is the first study to empirically evaluate the mortality of Amblyomma mixtum larvae caused by native entomopathogenic fungi (EPF) from cattle farm soils and the impact of the physicochemical conditions of those soils on the ability of EPF to kill ticks. The efficacy of 25 EPF strains isolated from cattle farms soils in Veracruz, Mexico, against A. mixtum ticks was evaluated using a larval immersion test. Physicochemical analyses of the soils where the EPF were isolated were carried out, and the results were correlated with the obtained mortality. The MaV25 strain showed a mortality of 36.55% (P < 0.05), followed by MaV57 with 27.30%, MaV08 with 26.21%, and MaV31 with 24.32% (P < 0.05). Nitrogen and potassium are nutritional components of soils that seem to be associated with mortality caused by the evaluated fungal strains. This is the first study in Mexico where the effect of EPF against A. mixtum is evaluated and also is the first study in the world that uses native strains from livestock soils against larvae of this tick. It is necessary to determine the virulence characteristics of EPF on A. mixtum to improve knowledge of fungus-tick interactions (Metarhizium anisopliae-A. mixtum).

Molecular detection of Coxiella-like endosymbionts and absence of Coxiella burnetii in Amblyomma mixtum from Veracruz, Mexico.

Ticks are obligate ectoparasites associated with a wide range of vertebrate hosts, including domestic animals. Moreover, ticks are capable of transmitting many pathogens such as Coxiella. To date, Coxiella burnetii, the etiological agent of coxiellosis or Q fever, is the only valid species of the genera. Nevertheless, a wide range of agents denominated Coxiella-like have been detected in recent studies, mainly associated with ticks. The pathogenicity of these Coxiella-like agents is controversial as some of them can infect both birds and humans. In Mexico, knowledge about Q fever is scarce and limited to historical serological records, and there is an overall lack of molecular proof of any agent of the genus Coxiella circulating in the country. Therefore, the aim of this study was to detect the presence of Coxiella in ticks associated with cattle in all 10 regions of Veracruz, Mexico. To accomplish this objective, first, we identified ticks collected from cattle and horses in Veracruz. Then, for Coxiella detection, DNA extraction from ticks and PCR amplification of the 16S-rDNA of Coxiella was performed. Finally, we performed a phylogenetic reconstruction to determine the Coxiella lineages detected. From the 10 regions sampled we collected 888 ticks grouped in 180 pools, and only five Amblyomma mixtum from the locality of Castán, and one from Los Angeles from Tuxpan were found positive, which represents a frequency of 20% for each locality. This study represents the first attempt at molecular detection of Coxiella in ticks associated with cattle in the state of Veracruz, the major livestock producer in the country. The findings of the present study are relevant as they establish a precedent regarding the circulation of Coxiella-like agents, as well as the absence in three municipalities of the state of Veracruz of C. burnetii, an abortive agent of livestock importance.

New Identification Tools for the Nymphs of Three Amblyomma spp. Koch (Ixodida: Ixodidae) in South Texas.

Taxonomic uncertainties and morphologic and molecular similarities may lead to incorrect or incomplete species identifications of immature ticks. This problem can be compounded when the diagnostic morphological features used are unreliable, unstable, or difficult to view. Our study attempts to sort out the similar morphologies of three Amblyomma spp. nymphs with partially overlapping geographic distributions in South Texas. Amblyomma americanum (L.), Amblyomma mixtum Koch, and Amblyomma tenellum Koch are three closely related species with similar nymphs and larvae. Previous attempts to morphologically distinguish among nymphs of these species have relied on difficult-to-observe and unreliable characters. Over the course of decades of routine diagnostic work with these ticks, we have observed and discovered consistent and useful morphologic features sufficient to practically distinguish among these nymphs. We confirmed our morphological studies with molecular genetic evidence (i.e., 12S mitochondrial genes), and we propose that practical, rapid morphological species-level identification of nymphs of the three named species is now possible with confidence.

Amblyomma mixtum free-living stages: Inferences on dry and wet seasons use, preference, and niche width in an agroecosystem (Yopal, Casanare, Colombia).

The formulation of effective control strategies for any pest species generally involves the study of habitat use and preference and niche width in anthropogenically transformed natural landscapes. We evaluated whether the use, habitat preference, and niche range of the Amblyomma mixtum tick changed between stages, habitats, and seasonality (dry-wet seasons 2019) on a farm in Yopal (Casanare, Colombia). The presence and relative abundance of free-living larvae, nymphs, and adults was quantified in four different habitats according to the type of vegetation cover (Riparian Forest, Cocoa Crop, King Grass Crop, and Star Grass Paddock). Habitat availability was estimated, environmental variables were analyzed, and various indices of habitat use and preference, and niche width were calculated. A. mixtum’s habitat use and preference, and niche width changed between stages, habitat types, and time of the year. The total abundance of A. mixtum was an order of magnitude greater in the dry season than the wet season. In the dry season, all stages used all habitats, while A. mixtum adults used all the habitats in both seasons. In the dry season, nymphs and larvae preferred three out of the four habitats, while adults preferred the King Grass Crop. In the wet season, nymphs and larvae preferred two habitats, whereas the adults preferred the King Grass Crop. The value of the niche width index was high for larvae, nymphs, and adults in the dry season, while it was high only for adults in the wet season. Thus, A. mixtum’s vast environmental tolerance and niche breadth allows the species to use and colonize changing habitats (unstable or temporary) with fluctuating environmental conditions (e.g., King Grass Crop), potentially keeping a stable population over time and making it an extremely resistant species. However, the wet flooding season in Yopal may exceed A. mixtum’s stages’ tolerances.

Rickettsia spp. in ticks from a tropical dry forest reserve on Mexico's Pacific Coast

The present study analyzes the diversity of bacteria of the genus Rickettsia in ticks collected from wild mammals and vegetation at the Chamela Biological Station (EBCh), Jalisco, Mexico, a core area in the Chamela-Cuixmala Biosphere Reserve, which is characterized by the presence of tropical dry forest, one of the most threatened ecosystems in the world. Ticks were collected during April and November 2018 and 2019, determined to species, and subsequently processed for rickettsiae. Genomic DNA was extracted from each of 349 ticks (198 from mammals, 151 from vegetation) and screened for Rickettsia by targeting the gltA and ompA genes. Overall, 75 ticks (21.5%) were positive for rickettsiae (46 from mammals, 29 from vegetation). Through BLASTn and maximum likelihood analysis, four Rickettsia taxa were identified. Only Rickettsia amblyommatis had been previously recorded in the vicinity of the EBCh, and we confirm its presence in this reserve, associated with Amblyomma mixtum, Amblyomma cf. oblongoguttatum and Amblyomma parvum. Additionally, we record for the first time at EBCh the taxa Rickettsia parkeri strain Atlantic rainforest, which is known to cause spotted fever illness in humans, detected in Amblyomma ovale; Rickettsia bellii in A. parvum and Ornithodoros talaje; and an undescribed Rickettsia sp. in Ixodes sinaloa.

Description of human infestations by ticks in Panama and Costa Rica

Tick bites in humans are associated with the transmission of pathogens, anaphylactic shock, paralysis, and secondary infections. In this work we described six cases of tick bites in patients from Panama and Costa Rica. These bites were provoked for adults of Ornithodoros puertoricensis, Amblyomma cf. oblongoguttatum, Amblyomma ovale, and Ixodes cf. boliviensis, and a nymph of Amblyomma mixtum. The relationships of these species of ticks with the environment are explained. Among the reactions observed in the patients there are blisters, maculo-papular rash, granuloma, lymphadenopathy, and erythema migrans-like rash, but none referred symptoms compatible with an infectious disease. In the collected ticks a PCR battery was developed to rule out Borrelia, Rickettsia, Anaplasmataceae, and Coxiella diseases to the ticks from the cases 1, 2, 3 and 4, with negative results. Although no pathogen infections were evidenced, these finding indicate that the tick bites constitute a public health problem what goes unnoticed in many countries.

Molecular detection of Rickettsia amblyommatis and Rickettsia parkeri in ticks collected from wild pigs in Campeche, Mexico

Tick-borne rickettsioses are caused at least by 15 species of Rickettsia of the Spotted fever group, which represent a major emerging and re-emerging public health problem worldwide. Some of these microorganisms have complex cycles involving the interaction of multiple species of ticks and wild and domestic mammals. Rickettsia infection was investigated in ticks collected from wild pigs at six localities in southeastern Mexico. We collected and tested 196 ticks belonging to four species, including Amblyomma maculatum, Amblyomma mixtum, Amblyomma ovale and Riphicephalus microplus, from 13 of 20 (65%) wild pigs sampled. Overall, Rickettsia DNA was detected in 13.8% of ticks tested (10 ♂ and 17 ♀). Of the 27 Rickettsia-positive ticks, six were A. maculatum, and 21 A. mixtum. Sequencing and phylogenetic analysis of the gltA and ompB genes revealed the presence of Rickettsia parkeri sensu stricto in one female A. maculatum and Rickettsia amblyommatis in five A. maculatum (2 ♂, 3 ♀) and 21 A. mixtum ticks (8 ♂, 13 ♀). The finding of two rickettsial agents in ticks collected from a wild pig population that is regularly captured and kept in captivity or hunted as a source of food raises concern about potential disease transmission to humans and domestic animals. However, more investigations are needed to further understand the ecology of Rickettsia species in free-ranging animals and their implications for human health.